Page 117 - CITS - Fitter Trade Practical - Volume -2

FITTER - CITS

EXERCISE 77 : Slip Gauges

Objectives

At the end of this exercise you shall be able to
• define the features of slip gauges
• state the different grades of slip gauges
• state the number of slips in standard
• state the precautions and application of slip gauges.

Slip gauges
Slip gauges are gauge blocks used as standards for precision length measurement. (Fig 1) These are made in
sets and consist of a number of hardened blocks, made of high grade steel with low thermal expansion. They are
hardened throughout, and heat treated further for stabilization. The two opposite measuring faces of each block
are lapped flat and parallel to a definite size within extremely close tolerances.

Fig 1

These slip gauges are available in various sets with different numbers. (Fig 2) (Ref.Table 1)

Fig 2

A particular size can be built up by wringing individual slip gauges together. (Figs 3 & 4)

Wringing is the act of joining the slip gauges together while building up to sizes.
Some sets of slip gauges also contain protector slips of some standard thickness made from higher wear-resistant
steel or tungsten carbide. These are used for protecting the exposed faces of the slip gauge pack from damage.
Grades

Grade ‘00’ accuracy
It is a calibration grade used as a standard for reference to test all the other grades.
Grade ‘0’ accuracy
It is an inspection grade meant for inspection purposes.

Grade I accuracy
Workshop grade for precision tool room applications.

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